The invention relates to apparatus for and methods of handling biological sample containers, including removal and subsequent replacement of lids of the containers while the containers are being conveyed between positions. Especially, but not exclusively, the invention relates to the handling of Q-trays, omni trays, petri dishes and well plates.
The processing of biological and microbiological samples often includes the use of arraying and microarraying methods. These methods use moveable arrays of pins or needles to transfer small amounts of sample from one container to another. For example, a cell culture or colony may be grown in a container of one type, and samples from the colony may be transferred to other containers for subsequent testing.
The pin array is typically moved by computer control over an arraying surface on which the containers are arranged in appropriate positions. It is desirable that the containers are held firmly in place during the arraying, to allow accurate collecting and depositing of samples by the pins. Also, processing may be conducted in large volumes, with many samples requiring to be transferred in a short time. Therefore, it is further desirable that pluralities of containers can be placed on and removed from the arraying surface quickly and accurately.
Several different sizes and shapes of container are typically used, such as large rectangular Q-trays, smaller rectangular well plates (micro-tite plates) and omni trays, and circular petri dishes. The containers generally have lids to keep their contents safe from spillage and contamination. The style of lid differs between container types. Clearly, the lids need to be removed prior to arraying and replaced again afterwards. Automation of the lid removal and replacement facilitates the arraying process, so that a larger volume of containers can be handled in a given time.
A conventional method of delivering containers to the arraying surface uses vacuum suckers to remove and replace the lids. A container with a lid is moved, for example on a conveyor belt, to a lid-removal position at which it is brought to a standstill. A vacuum sucker is lowered down to contact the lid of the container, the vacuum causing the sucker to adhere to the lid. The vacuum sucker is then raised, carrying the lid with it. The container is then moved on to its arraying position. After arraying, the container is moved back to the lid-removal position and brought to a standstill again. The vacuum sucker is moved downward again so that the lid is lowered on the container. Removal of the vacuum releases the lid from the sucker. The container, with its lid, is then moved on from the lid-removal position.
The removal and replacement of lids in this way tends to slow down the operation of delivering and removing containers for arraying. Also, it is necessary to accurately locate a container under the vacuum sucker, which requires precise control of the conveyor. This is particularly important for lid replacement, when a lid and container need to be precisely aligned for lid replacement to be successful. This becomes increasingly difficult to achieve if a quantity of containers are moved together, which it is desirable to be able to do to increase the efficiency of the arraying process.
Hence, there is a requirement for an improved method of, and apparatus for, handling biological sample containers.